powdery mildew on the leaves of maple purple-leaf acer pseudoplatanus l

acer bel branch burgundy color cultural deciduous decorative dew disease ecological ecology erysiphales family flora foliage form fungal grade infected leaf leaves maple mealy mildew muchnistorosyany mushrooms nature parasite perisporiales plant powdery problem pseudoplanetree pseudoplatanus purple purpleleaf raid sapindaceae soapberry struck summer tree version white yavor